An Automated Spreading Resistance Test Facility

An automated spreading resistance test facility has been designed and constructed at the Allentown Works of the Western Electric Co. This system has been shown to provide a rapid, semi-nondestructive, and reproducible measurement of epitaxial layer resistivity which can be used in a production environment. The system has the advantages of operator independence, well protected probes, and four-inch capability. Surface or in-depth measurements can be performed with on-line calculations of resistivity and impurity concentration. Cycle time is less than five seconds per measurement and system reproducibility is ± 1.3% (lS).